For a better understanding of the solution/explanation provided here, please go through the diagram in the file that has been attached.
To solve this question we will use the following theorem: "An Angle formed by a chord and a tangent that intersect on a circle is half the measure of the intercepted arc ".
As can be seen from the diagram, the intercepted arc is BC and it's angle is
.
Therefore, as per the theorem,


Thus the third option is the correct option.